1. Field of the Invention
The invention relates to a textile material with an HF transponder according to the precharacterising part of claim 1.
To identify goods during production, logistics, distribution and repair, increasingly transponders are used that in relation to legibility and data volume, as well as manipulation reliability, are superior to common barcodes. The use of transponders is also striven for in the case of textile goods; however, due to their flexible character and the necessity to clean them in hot and/or chemically corrosive media, the requirements are more stringent.
For example, a transponder must not negatively affect the intended use of textile goods; it must be resistant to thermal and chemical influences; and it must nevertheless operate so as be physically reliable.
2. Description of the Related Art
It has been known to equip textile labels with transponders that operate in the 13 MHz range. M-field radiators with coreless coils, also known as air coils, are used as antennas. The air coils can be designed in the form of conductive metal tracks on film carriers. Combinations comprising a film layer and a textile layer, e.g. as laminates, are usually incompatible with the intended use and with the process of cleaning the textile goods. Such film can become detached, partly or entirely, and/or can become damaged. However, direct integration of an air coil in a textile layer, i.e. without a film carrier, is generally problematical due to the low-ohmic and narrow-band character of a coil antenna.
However, while embroidery techniques make it possible to produce a coil from a continuous electrically conductive thread, the reproducibility of the coil geometry and the stability of this geometry during intended use of the textile goods is very poor so that the resonance frequency of the coil cannot reliably be set to the working frequency and/or cannot be held constant. Consequently the range of data transmission is shortened.
With the use of weaving techniques a reproducible and stable geometry can be achieved. However, with currently know techniques it is not possible to implement a coil antenna from a continuous electrically conductive thread in the form of a concentric spiral. Instead, warp threads and weft threads have to be multiply galvanically interconnected in order to create a coil shape in the form of a concentric spiral. The transition resistance of each of these connections increases loss and negatively affects the coil quality. Consequently the range of data transmission is also shortened.
It is the object of the invention to create a textile material with an integrated HF transponder, which makes it possible to use the textile material as an antenna that works in a physically reliable manner.